The present invention relates to an integrated heating, ventilation, air conditioning, and refrigeration system. More particularly, the present invention relates to a system that combines various functions of the HVAC system and the refrigeration system into a single, integrated system that utilizes the refrigeration system, airflow controls, and an integrated control system 325 to condition an indoor environment.
Retail settings (e.g., retail food store applications such as grocery or convenient stores, supermarkets, or other locations) typically employ separate heating, ventilation, and air conditioning (“HVAC”) and refrigeration systems to condition respective environments within the retail setting. For example, a typical retail setting may have several roof-top air-conditioners with different cooling capacities (e.g., 3 to 30 tons cooling capacity) to condition the open space within the retail setting. These rooftop units also may include electric resistance heaters for winter heating. In addition, desiccant wheel type dehumidification systems are sometimes used for dehumidifying the open space.
Often, retail settings also include one or more enclosed spaces (e.g., open or enclosed merchandisers, walk-in coolers, freezers, etc.) that must be cooled or refrigerated at temperatures that are substantially different from the desired conditions of the open space. For refrigeration loads in these enclosed spaces, two or more parallel compressor “rack” systems are often used to cool or refrigerate the enclosed spaces. Currently, the HVAC system and the refrigeration system(s) in retail settings are separate and distinct from each other, and are controlled by separate, independent control systems.
Some retail settings employ mechanical subcooling in the refrigeration system to cool refrigerant in one portion of the refrigerant circuit using the same refrigerant in another portion of the refrigerant circuit. In these retail settings, liquid refrigerant in one area of the refrigerant circuit is cooled to approximately 50 degrees Fahrenheit by refrigerant from another portion of the same refrigerant circuit before being fed to low temperature loads in the retail setting.